There are still plenty of panels that sport aging analog VHF navcomm radios and when it comes time to pull the trigger on an upgrade, the logical choice for many is to replace them with GPS. And that made us wonder why Scotland-based Trig Avionics brought the fresh TX56/TX57 navcomm radios to market over a new GPS-equipped rig.
“We see two applications for this: classic two-seat trainers and as backup to integrated navigators from Avidyne and Garmin,” Trig’s Andy Davis told us during a demo at AirVenture. If your airplane fits those targets, or falls somewhere in between, here’s a look at the new radio and a deep dive into its rich user interface.
THE REAL WORLD
In general—and we know there are still flight schools with trainers equipped with old panels that teach IFR flying by tracking VORs and shooting ground-based ILS approaches—shops tell us customers started abandoning ground-based VHF navigation when the FAA announced plans to eliminate VOR and ILS ground hardware. Then, Garmin came out with its budget-based GPS-only integrated navigators, and sales have been brisk for a wide chunk of the market—especially for VFR panels.
But, there are also plenty of panels with self-contained GPS navigators (Garmin GNS, GTN and Avidyne IFDs) used as the primary, but the backups are aging King KX155, Narco MK12D and even Collins Microline radios. Some of these radios still work, some half work and some are completely inop. If you’re concerned about GPS outages and still want a VHF navcomm for backup, we think Trig’s TX56/TX57 rigs are worth considering.
FEATURES AND INTERFACE
Trig’s new $4175 TX56 (for 14- and 28-volt electrical systems) and the TX57 (a 16-watt version for 28-volt systems) trickle down from Trig’s successful and nicely equipped TY96-series comm transceivers, but are equipped with a built-in VHF navigation receiver. Versions with 25-kHz spacing are also available.
Like the comm radios, the TX-series navcomms are space-savers, standing a slim 1.3 inches tall. Basic functions are straightforward, and the controls have a durable and positive feel. The left bezel knob serves double duty as an on/off control and adjusts the audio volume for both the comm and the nav. There’s autosquelch, of course, but pressing the volume/power knob opens the squelch.
There’s a lot packed into these radios, but we think Trig did a good job of using what little real estate that is available on the small display. The display is divided into two windows. The left part of the screen shows the primary and standby frequencies and icons to indicate the operating mode of the communication radio. The right part of the screen shows the primary and standby frequencies, plus helpful icons to indicate the operating mode of the navigation radio. The controls are shared between the communication radio and the navigation radio, and which is being controlled is shown by the size of the corresponding display window.
In comm radio mode, the dividing bar moves to the right and the comm radio window occupies most of the screen. In that mode, the knobs and buttons control the functions of the comm radio.
In navigation radio mode, the dividing bar moves to the left and the navigation radio window occupies most of the screen. In nav mode, the knobs and buttons specifically control the function of the navigation radio. If you don’t have a CDI connected to the TX radio, the built-in OBS display serves as an integrated CDI. The left/right movement of the on-screen needle indicates the course position relative to the aircraft position. When the needle is in the middle, the aircraft is on the selected course. A To/From flag will be shown to indicate whether the course is inbound or outbound. The right knobs (tuning knobs) act as OBS knobs, and allow you to select the desired VOR radial. As a shortcut, if the tuned VOR is in range, pressing on the end of the tuning knob will slew the OBS value to match the current radial.
If you have a conventional CDI or a digital CDI on a glass display, the OBS knob on the CDI itself will of course control the radial selected for the TX56/57 CDI, and the left/right movement of the main CDI needle will be repeated on the screen of the TX radio. It’s a complete nav interface for sure, but worth mentioning is a limitation if you use King CDIs equipped with built-in VOR/LOC converters, as the Trig OBS mode won’t work. Talk this through with your installer if that’s a concern.
When the Trig’s nav receiver is tuned to a VOR that is in range, the system will decode the radial that you are flying over. The normal display is the radial from the beacon—or the outbound radial. If you want to see the magnetic track to follow to get to the beacon, pressing the T/F button will flip the display to show bearings to the beacon. Pressing it again will toggle back to displaying the radial from the beacon.
The power/volume knob (when the radio is in nav mode)serves as a means to toggle between voice mode and ident mode on the nav radio’s receiver. Voice mode is used to listen to ATIS or other communications on a VOR station. In voice mode the display shows a V icon. Ident mode filters out most of the background noise (and voice transmission) and allows you to listen just to the Morse code identifier. This is especially useful when the signal is faint. Ident mode shows an ID icon.
Interestingly, if you’re using the radio without an audio panel, a third choice is available, which is to mute the Nav audio altogether—something you would do by deselecting the nav audio on an audio panel.
SMART FEATURES
The comm and nav radios include a dual-frequency listen feature, and pressing the Mon button toggles this feature on and off. The monitor mode can even be enabled separately for the comm and nav radios by simply pressing the Mon button while on the appropriate screen. This monitor function is a good utility when you only have a single radio because it’s almost like having dual receivers. There’s even a scan mode.
When the comm monitor is active, an icon (labeled +2) appears next to the standby frequency and the radio will scan between the active and standby frequencies listening for transmissions. The primary channel has priority; in other words, a transmission on the primary channel will interrupt the secondary channel. As an aid to identifying which channel is active, the RX icon will annunciate next to the active channel and the secondary channel will appear slightly quieter than the primary. If your radio is wired for stereo and you are using a stereo headset, the secondary channel will also appear to be to the right of the primary channel—pretty smart and useful for identifying what you’re listening to.
The Play button on the upper left of the bezel is for the built-in audio recorder. Pressing it will automatically replay the previous transmission received from ATC. During playback the PB icon will be displayed on the screen. If a new transmission is received during playback, the playback is canceled and the live transmission will be heard instead.
FREQUENCY DATABASE
The USB port on the front of the bezel isn’t, to our disappointment, for external charging. Instead, it’s used for loading data into the radio. This feature trickles down from Trig’s comm transceiver. There are three types of databases containing frequencies and station identifiers for both comm and nav frequencies. One is stored in the radio and configured by the pilot and will always be available. Another is a list of the 10 most recently used frequencies and will be populated automatically as you use the radio. The third is only available if the radio has been connected to a compatible GPS receiver, and it contains frequencies loaded from the GPS database.
To access these databases, press the Mem button while in the applicable mode (there are both comm databases and nav databases). The right part of the window will be replaced with the database screen, which always starts on the pilot- created database. The large knob moves the highlighted cursor, and the small knob selects the value at the cursor.
Airfield or facility identifiers are in alphabetical order, and all you have to do is scroll through the identifiers until you find the one that you want. Move the cursor using the large knob to highlight the station type—GND, TWR, APPR and so forth. There is also a memory bank of the 10 most recent frequencies that you have used. From the initial memory screen, move the cursor using the large knob to highlight the Memory caption, and turn the small knob to select the Recent database. Move the highlight onto the frequency, and you can scroll through the 10 most recently used frequencies.
Pressing the Mem button at any time puts the currently selected result into the standby frequency and returns to the normal operating screen. A third type of database in the radio is loaded by your GPS receiver (yes, Garmin units will work via RS-232 serial data) and will contain airfields appropriate to your current route of flight, as we’ll as nearby beacons and ILS/LOC frequencies. It is accessed exactly the same way as the built-in database, except that you first select the remote data source using the large knob (to highlight the database field) and the small knob (to select the GPS data source). The only difference is that airfield and beacon identifiers are usually ordered by how close they are to your route, rather than in alphabetical order.
If all of this seems like more functions than you will use, you may be right. Still, these are advanced features one might expect from an ultramodern navcomm radio and we think Trig did a good job executing the deep interface.
INSTALLING THEM
Trig’s installation is straightforward, and what you would expect with a modern navcomm. There’s a 25-pin D-type connector for the communication radio and audio system, and a 44-pin D-type connector for the navigation receiver. There are two RF antenna connectors—one for the communications radio and one for the navigation receiver.
The radios have built-in intercoms and provide voice-activated ICS operation between the pilot and copilot, with auxiliary audio input (and stereo music) to be played over the headphone outputs. Compared to an advanced audio panel it’s basic, and the built-in ICS is really intended for use in aircraft where a conventional audio panel is not installed—good in a two-place trainer, as one example.
One of the things that Trig worked hard on is compatibility with legacy and newer navigation indicators. That’s imperative for any new navcomm, in our view, because there are a wide variety of nav indicators to interface with—everything from analog HSIs to electronic flight displays. The TX nav receiver can even work with older King CDIs. That means you can pull out a KX155 and not have the expense of sourcing a new indicator. Still, be sure to have your shop bench test the indicator to ensure the meter assemblies and related circuitry are healthy.
During our demo, the primary TX56 was connected to a new Aspen EFD1000 Pro Max PFD and the second radio was connected to Trig’s indicator. Trig said it designed the radios to also work with Garmin G3X Touch integrated flight displays (and the GI 275 EHSI) and Dynon SkyView displays. Got a newer (relatively speaking) DME like a King KN53? The Trig radio will channel it. Kudos to Trig for good interconnect compatibility.
To help with troubleshooting, should the VHF radio detect a catastrophic internal failure, the screen will indicate Fault and a brief statement of the problem. You can make note of the fault message at the bottom of the screen and pass that information along to your avionics shop. The fault may be cleared by recycling the power to the radio, but if the fault is still present the message will reappear—just like a dreaded Check Engine light.
See a video demo of the Trig radio at http://tinyurl.com/j95ht2a
SHOP WISELY
We think Trig has a worthy radio with the TX series and it’s a huge leap in technology compared to vintage analog navcomms. But before diving into any navcomm installation, consider how you fly. If you haven’t dialed in a VOR frequency or flown an ILS approach in years, you probably don’t need a conventional radio.
For VFR missions, tablet navigation apps and even portable GPS navigators might be good enough to skip ground-based navaids altogether as so many buyers have done. For IFR, a WAAS GPS installation may be a better choice and more so if an ADS-B upgrade is done at the same time.
If you’ve priced a comm/GPS installation like Garmin’s $7595 touchscreen GNC 355, you’ll know the price can flirt with $10,000, so at just shy of $4200 for Trig’s radio, (or $4995 for Garmin’s GNC 255 navcomm) the install might end up around $7000. In the end, the comm/GPS will offer more utility for that larger investment. In some applications (not all) the ability to fly GPS approaches is generally worth the price delta.
Visit www.trigavionics.com.